bsd/kern/kern_panicinfo.c

   1 /*
   2  * Copyright (c) 2002-2006 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #include <sys/param.h>
  30 #include <sys/fcntl.h>
  31 #include <sys/malloc.h>
  32 #include <sys/proc.h>
  33 #include <sys/sysctl.h>
  34 #include <sys/vnode.h>
  35 #include <sys/vm.h>
  36 #include <sys/systm.h>
  37
  38 #include <mach/mach_types.h>
  39 #include <mach/kern_return.h>
  40 #include <kern/kern_types.h>
  41 #include <vm/vm_kern.h>
  42
  43
  44 /* prototypes not exported by osfmk/console. */
  45 extern void panic_dialog_test( void );
  46 extern int  panic_dialog_set_image( const unsigned char * ptr, unsigned int size );
  47 extern void panic_dialog_get_image( unsigned char ** ptr, unsigned int * size );
  48
  49 /* make the compiler happy */
  50 extern int sysctl_dopanicinfo(int *, u_int, user_addr_t, size_t *, user_addr_t, size_t, struct proc *);
  51
  52
  53 #define PANIC_IMAGE_SIZE_LIMIT  (32 * 4096)                             /* 128K - Maximum amount of memory consumed for the panic UI */
  54 #define KERN_PANICINFO_TEST     (KERN_PANICINFO_IMAGE+2)                /* Allow the panic UI to be tested by root without causing a panic */
  55
  56 /* Local data */
  57 static int image_size_limit = PANIC_IMAGE_SIZE_LIMIT;
  58
  59 __private_extern__ int
  60 sysctl_dopanicinfo(int *name, u_int namelen, user_addr_t oldp, size_t *oldlenp,
  61                    user_addr_t newp, size_t newlen, struct proc *p)
  62 {
  63         int error = 0;
  64         vm_offset_t newimage = (vm_offset_t )NULL;
  65         kern_return_t   kret;
  66         unsigned char * prev_image_ptr;
  67         unsigned int prev_image_size;
  68
  69         /* all sysctl names at this level are terminal */
  70         if (namelen != 1)
  71                 return (ENOTDIR);               /* overloaded */
  72
  73         if ( (error = proc_suser(p)) )  /* must be super user to muck with image */
  74                 return (error);
  75
  76         switch (name[0]) {
  77         default:
  78                 return (ENOTSUP);
  79
  80         case KERN_PANICINFO_TEST:
  81
  82                 panic_dialog_test();
  83                 return (0);
  84
  85         case KERN_PANICINFO_MAXSIZE:
  86
  87                 /* return the image size limits */
  88
  89                 newlen = 0;
  90                 newp = USER_ADDR_NULL;
  91
  92                 error = sysctl_int(oldp, oldlenp, newp, newlen, &image_size_limit);
  93
  94                 return (error);
  95
  96         case KERN_PANICINFO_IMAGE:
  97
  98                 /* If we have a new image, allocate wired kernel memory and copy it in from user space */
  99                 if ( newp != USER_ADDR_NULL ) {
 100
 101                         /* check the length of the incoming image before allocating space for it. */
 102                         if ( newlen > (size_t)image_size_limit )
 103                                 return (ENOMEM);
 104
 105                         /* allocate some kernel wired memory for the new image */
 106                         kret = kmem_alloc(kernel_map, &newimage, (vm_size_t)round_page(newlen));
 107
 108                         if (kret != KERN_SUCCESS) {
 109                                 switch (kret) {
 110                                 default:
 111                                         error = EINVAL;
 112                                         break;
 113                                 case KERN_NO_SPACE:
 114                                 case KERN_RESOURCE_SHORTAGE:
 115                                         error = ENOMEM;
 116                                         break;
 117                                 case KERN_PROTECTION_FAILURE:
 118                                         error = EPERM;
 119                                         break;
 120                                 }
 121
 122                                 return (error);
 123                         }
 124
 125                         /* copy the image in from user space */
 126                         if ( (error = copyin(newp, (char *) newimage, newlen)) )
 127                                 goto errout;
 128
 129                 } else {        /* setup to make the default image active */
 130
 131                         newimage = (vm_offset_t )NULL;
 132                         newlen = 0;
 133                 }
 134
 135                 /* get the current image location and size */
 136                 panic_dialog_get_image( &prev_image_ptr, &prev_image_size );
 137
 138                 /* did the caller request a copy of the previous image ? */
 139                 if ( oldp != USER_ADDR_NULL ) {
 140                         if ( *oldlenp < prev_image_size ) {
 141                                 error = ERANGE;
 142                                 goto errout;
 143                         }
 144
 145                         /* copy the image to user space or zero the size if the default image is active */
 146                         if ( prev_image_ptr != NULL ) {
 147                                 if ( (error = copyout( prev_image_ptr, oldp, prev_image_size )) )
 148                                         goto errout;
 149
 150                                 *oldlenp = prev_image_size;
 151                         }
 152                         else /* tell the user that the default image is active */
 153                                 *oldlenp = 0;
 154                 }
 155
 156                 /* Make the new image active, or reactivate the default image.
 157                    But, handle the special case of asking for the current image
 158                    without changing the current image.
 159                 */
 160
 161                 if ( !(oldp && newp == USER_ADDR_NULL) ) {
 162                         if ( (error = panic_dialog_set_image( (unsigned char *) newimage, newlen )) )
 163                                 goto errout;
 164
 165                         /* free the wired memory used by the previous image */
 166                         if ( prev_image_ptr != NULL ) {
 167                                 (void)kmem_free(kernel_map, (vm_offset_t) prev_image_ptr, (vm_size_t)round_page(prev_image_size));
 168                                 printf("Panic UI memory freed (%p)\n", (void *)round_page(prev_image_size));
 169                         }
 170                 }
 171
 172                 return (0);
 173
 174 errout:
 175                 if ( newimage != (vm_offset_t )NULL )
 176                         (void)kmem_free(kernel_map, newimage, (vm_size_t)round_page(newlen));
 177
 178                 return (error);
 179         }
 180 }